I have heard that for best accuracy a bore should be smaller at the muzzle than at the chamber end by a bit. Like for a 30 caliber maybe the bore diameter would be 0.3000 at the chamber end and 0.2998 at the muzzle end. If it is reversed tapered supposedly accuracy suffers. I would like to know more about this. What are the premium barrels supposed to be measuring and how big of a deal is it if the bore diameter increases a bit instead of decreases? Thanks, Rufous.